diff --git a/src/lib/testService.js b/src/lib/testService.js
index e0828f5..d0a9657 100644
--- a/src/lib/testService.js
+++ b/src/lib/testService.js
@@ -94,10 +94,14 @@ async function selectTestTopics(userId, isoWeekNumber) {
     const weekContent = await getCurrentWeekContent(isoWeekNumber);
 
     if (weekContent && weekContent.topics && weekContent.topics.length > 0) {
-      const primaryTopic = weekContent.topics[0]; // Use first topic as primary for now
-      const others = topics.filter(t => t.id !== primaryTopic.id);
-      const reviewTopics = sample(others, Math.min(5, others.length));
-      return { primaryTopic, reviewTopics, isReviewWeek: false };
+      const primaryTopic = weekContent.topics[0];
+      if (!primaryTopic?.id) {
+        console.warn('[Test] First curriculum topic has no id — falling back to hash');
+      } else {
+        const others = topics.filter(t => t.id !== primaryTopic.id);
+        const reviewTopics = sample(others, Math.min(5, others.length));
+        return { primaryTopic, reviewTopics, isReviewWeek: false };
+      }
     }
   } catch (e) {
     console.warn('[Test] Curriculum lookup failed, falling back to hash:', e.message);